It is said that the enteric environment of people of modern times has deteriorated because of undue stress, unbalanced diet, and irregular living habits, such as lack of sleep. The enteric environment is closely related to the health condition, and common symptoms such as extreme fatigue, and excessive sensitivity to cold, shoulder stiffness, skin problems, and lower back pain caused by blood circulation disorder are considered to result from a deteriorated enteric environment. While such symptoms may be relieved if the enteric environment is brought back to a normal state by modifying irregular living habits, it is not easy for busy people of modern times to modify their living habits. Accordingly, food products, functional food products, and pharmaceutical products that can alleviate such symptoms and are safe, and thus can be routinely and continuously ingested, have been desired.
In the field of animal husbandry, the enteric environment of livestock animals deteriorates due to stresses imposed thereon through group feeding or administration of drugs such as vaccines aimed at an improvement in productivity. This raises problems such as inhibited growth, worsened stool odor, and deteriorated quality of flesh and eggs. While antibiotics or the like have heretofore been used to avoid such problems, antibiotics are administered at low concentrations for a long period of time. Accordingly, the development of antibiotic-resistant strains or the influence of remaining antibiotics on humans has become an issue of concern. Under such circumstances, development of feed or feed additive that has overcome the problems as described above, that is, a feed or feed additive that is highly safe and can be routinely and continuously used, has been awaited in the field of animal husbandry.
In view of enhanced health consciousness of recent years, lactic acid bacteria have drawn attention as components that exert useful biological activity on humans and animals (so-called “functional components”). Up to the present, each of the various types of lactic acid bacteria has been known to exert a particular type of biological activity among a wide variety of biological activity, such as regulation of the functions of the intestines, anti-allergic activity, cholesterol-lowering activity, or antihypertensive activity, upon oral administration to humans or animals (Non-Patent Document 1). In recent years, also, it has been reported that lactic acid bacteria (the Lactobacillus johnsonii La1 strain, also referred to as “LC1 lactic acid bacteria”) regulate the autonomic nervous system through the central histaminergic system or the hypothalamic suprachiasmatic nucleus in which the circadian clock is present, thereby affecting the blood pressure, body temperature, and other properties (Non-Patent Document 2). Accordingly, research on lactic acid bacterial strains with novel biological activity has been in progress.
While a wide variety of lactic acid bacterial species are known to exert useful biological activity on humans and animals as described above, lactic acid bacteria that would effectively ameliorating fatigue or blood circulation disorder have not yet been discovered. In addition, effects attained by providing livestock animals or the like with lactic acid bacteria that have effects of ameliorating fatigue or blood circulation disorder, in particular, effects of reducing stool odor, or promoting growth have not yet been examined.